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Area Forecast Discussion (AFD)

Issued by Pendleton, OR (PDT)

FXUS66 KPDT 221734 AAA

Area Forecast Discussion...Updated
National Weather Service Pendleton OR
1033 AM PDT Thu Aug 22 2019

Updated aviation discussion

.SHORT TERM...Short wave and cold front moving east into idaho
this morning. Cool upslope flow into the northeast Oregon 
mountains resulting in mostly cloudy skies. This will decrease 
during the day. Remainder of the forecast area is mostly sunny and
should remain so for the day. Cooler temperatures with highs only
in the 70s to lower 80s. Locally breezy west winds will diminish 
at sunset. 12z models continue to indicate a breezy to windy day
Saturday with another system moving across the Pacific northwest.


.AVIATION...18Z TAFs...VFR conditions will prevail for the next 24 
hours. Skies will be partly to mostly cloudy over the eastern Oregon 
mountains today before clearing this evening. Elsewhere skies will 
be mainly clear though scattered clouds around 2500-3500 feet will 
linger at KRDM and KBDN for the next few hours. Winds will continue 
at 10 to 20 kts with gusts to 25 kts at KDLS through 03Z this 
evening. KRDM and KBDN may have some gusts to 20 kts this afternoon 
but otherwise winds will remain below 12 kts for the next 24 hours. 


.PREV DISCUSSION... /issued 117 AM PDT Thu Aug 22 2019/ 

SHORT TERM...Today through Saturday night...latest water vapor 
imagery shows an upper level trough over the inland northwest moving 
eastward. A band of showers behind a cold front will be exiting the 
area early this morning and the forecast will be dry for the rest of 
the short term period. Temperatures will be cool today with highs in 
the upper 70s to mid 80s lower elevations and mid 60s to mid 70s 
mountains. After a cool night tonight temperatures will warm to near 
normal on Friday and slightly above normal on Saturday. There will 
be some clouds from time to time but virtually no chance of rain. On 
Saturday afternoon and evening there will be a marine push and winds 
will pick up. It will become windy in the Columbia Gorge and 
Kittitas Valley and adjacent lowlands with winds of 25-35 mph and 
some higher gusts. 78 

LONG TERM...Sunday through Friday...A dry and stable northwest flow 
will prevail through most of the extended forecast period. Medium to 
long range models are in good agreement with this scenario. This 
pattern will result in mostly clear skies each day with near normal 
temperatures at first, but slowly warming to a few degrees above 
normal by the end of the extended period. Precipitation is not 
expected. By Friday, the models diverge from each other with the 
Canadian and ECMWF wanting to keep a ridge over the region and the 
GFS a broad upper trough and a stronger jet stream over the region. 
For now will not make any changes being that it is so far out in the 
future (day 8) and the uncertainty that far out is too great. It 
will be breezy to windy on Sunday afternoon and evening, but then 
winds will diminish overnight Sunday into Monday. This wind will be 
the result of a jet stream maximum over the area, but it will be 
pushed northward by a broad upper ridge by Monday. After that winds 
will be mainly diurnally terrain driven in all areas. 88


PDT  80  51  84  56 /  10   0   0   0 
ALW  83  57  87  63 /  10   0   0   0 
PSC  85  55  87  59 /   0   0   0   0 
YKM  84  52  86  56 /   0   0   0   0 
HRI  84  52  88  58 /   0   0   0   0 
ELN  80  54  84  57 /   0   0   0   0 
RDM  77  42  86  48 /   0   0   0   0 
LGD  76  47  84  53 /  20   0   0   0 
GCD  79  49  89  55 /  20   0   0   0 
DLS  81  56  87  59 /   0   0   0   0